First observation of o-Ps to p-Ps transition and first direct measurement of positronium hyperfine splitting with sub-THz light

Positronium is an ideal system for the research of the bound state QED. The hyperfine splitting of positronium (Ps-HFS, about 203 GHz) is an important observable but all previous measurements of Ps-HFS had been measured indirectly using Zeeman splitting. There might be the unknown systematic errors on the uniformity of magnetic field. We are trying to measure Ps-HFS directly using sub-THz radiation. We developed an optical system to accumulate high power (about 10 kW) radiation in a Fabry-Pérot resonant cavity and observed the positronium hyperfine transition for the first time.     

Phase diagram of electron-hole systems: Interplay between exciton Mott transition and quantum pair condensation

Quasi-thermal-equilibrium states of electron-hole (e-h) systems in photoexcited insulators are studied from a theoretical viewpoint, stressing the exciton Bose-Einstein condensation (BEC), the e-h BCS-type pair-condensed state, and the exciton Mott transition between an insulating exciton/biexciton gas phase and a metallic e-h plasma phase. We determine the quasi-equilibrium phase diagram of the e-h system at zero and finite temperatures with applying the dynamical mean-field theory (DMFT) to the e-h Hubbard model with both repulsive and attractive on-site interactions. Effects of inter-site interactions on the exciton Mott transition are also clarified with applying the extended DMFT to the extended e-h Hubbard model.     

Trajectory of neutron–neutron–C excited three-body state

The trajectory of the first excited Efimov state is investigated by using a renormalized zero-range three-body model for a system with two bound and one virtual two-body subsystems. The approach is applied to n–n–¹⁸C, where the n–n$n\text{–}n$ virtual energy and the three-body ground state are kept fixed. It is shown that such three-body excited state goes from a bound to a virtual state when the n–¹⁸C binding energy is increased. Results obtained for the n–¹⁹C elastic cross-section at low energies also show dominance of an S-matrix pole corresponding to a bound or virtual Efimov state. It is also presented a brief discussion of these findings in the context of ultracold atom physics with tunable scattering lengths.     

Trajectory of virtual, bound and resonant Efimov states

The pole trajectory of Efimov states for a three-body ααβ system with αα unbound and αβ bound is calculated using a zero-range Dirac-δ potential. It is shown that a three-body bound state turns into a virtual one by increasing the αβ binding energy. This result is consistent with previous results for three equal mass particles. The present approach considers the n-n-¹⁸C halo nucleus. However, the results have good perspective to be tested and applied in ultracold atomic systems, where one can realize such three-body configuration with tunable two-body interaction.     

Meson properties from a bag model compared to lattice theory and heavy ion experiments

A bag at temperature (T) with pressureB(T)=B(0)[1?(T/T _c )⁴] is shown to be consistent with recent lattice data on the π and the ρ mesons. The limiting temperature,T _l , of the pion bag from the Bekenstein entropy bound is lower than that of other mesons. This agrees with the thermal distribution of π,K and the ρ in heavy ion collisions, which (unlike proton-nucleus or pp data) show a marked difference inT of pion and other mesons in the mid-rapidity region.     

Synthesis of affinity column of phosphatidylinositol-3,4-diphosphate

Phosphatidylinositol polyphosphates (PIPx) are related with tyrosine kinase activation, cell proliferation and carcinogenesis. In order to investigate the action mechanism of PIPx, it is desirable to synthesize affinity column of PI-3,4-P2, which is expected to be able to isolate the binding proteins of PI-3,4-P2. Thyramine reacted with CH-Sepharose 4B giving column 13. The p-amino group of 3'-(1',2'-distearoyl-glyceryl)-1-(2-p-aminobenzyl)-3,4-di-O-phosphoryl-myo-inosityl phosphate (12) was diazotized, then diazo-coupled with column 13 to give PI-3,4-P2 affinity column 14. This PI-3,4-P2 affinity column is an effective tool to pick up binding proteins of PI-3,4-P2.     

Flexible Enantiodivergent Synthesis and Biological Activity of Mannostatin Analogues, New Cyclitol Glycosidase Inhibitors

Mannostatin A (1) is a new cyclitol inhibitor of glycoprotein processing. 2-Epimannostatin A (12) and its enantiomer (13) as well as their positional isomers (14, 15) were designed for probing structure-activity relationships in this class of glycosidase inhibitors. The analogues have been synthesized from (S)-4-((tert-butyldimethylsilyl)oxy)-2-cyclopentenone by an enantiodivergent strategy in a totally stereospecific fashion. Compound 13 showed inhibition against almond beta-glucosidase and is shown to be a topographical analogue of beta-D-glucopyranoside.     

Synthetic approaches to new anthracyclines: 4,11-dideoxy-2-hydroxy-β-rhodomycinone and its glycosides

(±)-2-Acetoxy-4,11-dideoxy-10-oxo-β-rhodomycinone [(±)-6a] was synthesized from the tricyclic quinone (1) by a short efficient route in an overall yield of about 54%. Reaction of (±)-6a with protected daunosamine followed by reduction and deprotection provided the optically active α-glycosidated anthracycline (II) with the 7S,9R,10R-configuration. Furthermore, the amino and aromatic hydroxy groups of II were methylated.     

Determination of impurities in bismuth by solid-liquid extraction and emission spectrography

Summary A high-purity bismuth metal or bismuth nitrate sample is dissolved in nitric acid and converted to solid basic bismuth nitrate by heating. Impurities such as iron, cobalt, copper, and zinc at the low ppm or ppb level are extracted from the solid with water and determined by DC arc emission spectrography.

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Zusammenfassung Hochgereinigtes Wismutmetall oder Wismutnitrat werden in Salpetersäure gelöst und durch Erhitzen in festes basisches Wismutnitrat übergeführt. Verunreinigungen wie Eisen, Kobalt, Kupfer und Zink in ppm- oder ppb-Mengen werden aus der festen Probe mit Wasser extrahiert und emissionsspektrographisch bestimmt.

     

Drying dissipative structures of aqueous solution of poly (ethylene glycol) on a cover glass

Macroscopic and microscopic dissipative structural patterns formed in the course of drying a series of poly (ethylene glycol) (PEG) having molecular weights ranging from 1,000 to 2×10⁶ in aqueous solution have been studied on a cover glass. The broad ring patterns of the hill accumulated with the polymers are formed irrespective of the molecular weights of PEG molecules. The single round hills are formed also in the center in the macroscopic scale, when the molecular weight is large. The characteristic convection flow of the polymers and the interactions among the polymers and substrate are important for the macroscopic pattern formation. Cross-like fractal patterns are observed, especially for the diluted solutions in the microscopic scale. These patterns are determined mainly by the electrostatic and polar interactions between the polymers and/or between the polymer and the substrate in the course of solidification. Interestingly, these microscopic patterns are reflected based on the shape and size of the PEG polymers.